**5. Conclusions: translational research on hydroponics from Arabidopsis to crops**

As described in Woodward and Bartel [1], research on Arabidopsis can sometimes directly translate into discoveries in crops. One example that they use is the expression of MYB12 in tomatoes, which derived from initial discoveries in Arabidopsis revealing increased production of flavonoids upon overexpression. The overexpression of MYB12 in tomatoes produces so much flavonoids, the color of the fruit changes from red to orange [47]. However, this small mustard family plant has a growth habit and life cycle so different from most crop plants, can lessons learned from hydroponic studies on Arabidopsis be translated to crops? The answer is: mostly. Most of the technical approaches used with Arabidopsis translate to crop plants with minor modification, except for those crops that are very large and need extra support for growth. The benefits of using Arabidopsis for investigating the different techniques of hydroponics are those that make it valued as a model organism, i.e., its size, well-characterized genome, and short generation time. In fact, given the depth of knowledge on gene function in Arabidopsis, current research on Arabidopsis hydroponics could apply more widely to studies on fast breeding crop plants for gene discovery, on target plants for herbicide and drug discovery, and on plants used for bioregenerative life support systems in space.

Adoption of some the techniques used in Arabidopsis hydroponics could decrease the cost and size (important for space studies) of enclosed test systems without changing the viability and yield of the crop plants grown in those systems. For example, the effects of space travel are varied and complicated. However, most of the work done to date has focused on the microgravity component of space flight without the proper control of having a 1-g set of plants growing in the same space vessel [29]. Because Arabidopsis is small and well characterized, the initial tests for the design and implementation of these proper controls may be more feasible (and the data achieved more insightful) for Arabidopsis than for the crops identified as "the best" space plants, i.e., durum and bread wheat, soybean, and potato. Once done with Arabidopsis, the work would translate to these other species.
